Musical instruments in the brass section such as the trumpet, French horn, flugelhorn, cornet, mellophone, baritone horn, euphonium, tuba, sousaphone and trombone , all of which have removable slides, must be cleaned periodically. Brushes have been developed and are available commercially for this task. All of these brushes are constructed from straight fibers or bristles which are mechanically bound to a pair of twisted metal wires which are flexible to some extent. The problem with such metal wires is the fact that if the plastic or rubber caps are separated from the ends of the wires, the sharp edged wire ends can scratch or actually punch through the soft brass , thin wall metal tubes of the musical instruments, particularly those which have sharp, small diameter turns. Twisted wire brushes are not particularly flexible and this further exacerbates the scrapping and scratching of the interior walls of the instruments. Many slides in musical instruments are formed with 180° turns and damage to the geometry of the slide can take place in the hands of a careless or young amateur musician.
Musical instruments and heat exchangers as well as laboratory glass ware are constructed with a wide range of lengths and diameters. A universal brush made from twisted wire is simply not available. to handle the different diameters and different lengths. Many brushes, in an attempt to accommodate different lengths merely have fibers at the end of a very long handle. If the brush needs to be pushed through a sharp bend which occurs at the mid portion of the instrument, heat exchanger or glass ware the portion of the brush not covered with fibers must be covered with a soft flexible sheath to protect the inner wall of the metal or glass tube from the much harder surface of the twisted wire brush.